Hypoxic Ischemic Encephalopathy in Children: CT Findings Related to Prognosis

PURPOSE: To evaluate prognosis-related CT findings in hypoxic ischemic encephalopathy. MATERIALS AND METHODS: For the purpose of prognosis, 28 children with a clinical history and CT findings suggestive of hypoxic ischemic encephalopathy (HIE) were restrospectively reviewed. The diagnostic criteria for HIE, as seen on CT scanning, were as follows : 1, ventricular collapse ; 2, effacement of cortical sulci ; 3, prominent enhancement of cortical vessels ; 4, poor differentiation of gray and white matter ; 5, reversal sign ; 6, obliteration of perimesencephalic cistern ; 7, high density on tentorial edge, as seen on precontrast scans ; and 8, low density in thalamus, brain stem and basal ganglia. On the basis of clinical outcome, we divided the patients into three groups, as follows : group I(good prognosis) ; group II(neurologic sequelae), and group III(vegetative state or expire), and among these, compared CT findings. RESULTS: There were thirteen patients in group I, six in group II, and nine in group III. Ventricular collapse, effacement of cortical sulci, and prominent enhancement of cortical vessels were noted in all groups, whereas poor differentiation of gray and white matter, reversal sign, obliteration of perimesencephalic cistern, high density on tentorial edge, on precontrast scan, and low density in brain stem and basal ganglia were observed only in groups II and III. CONCLUSION: CT findings showed distinct differences between groups in whom prognosis was good, and in whom it was poor. An awareness of poor prognostic CT findings may be clinically helpful in the evaluation of patients with hypoxic ischemic encephalopathy.

Image Viewing Station for MR and SPECT: Using Personal Computer

PURPOSE: Macro language was programmed to analyze and process on Macintosh personal computers GE MR imagesdigitally transferred from the MR main computer, with special interest in the interpretation of information such as patients data and imaging parameters under each image header. By this method, raw data(files) of certain patients may be digitally stored on a hard disk or CD ROM, and the quantitative analysis, interpretation anddisplay is possible. MATERIALS AND METHODS: Patients and images were randomly selected. 4.X MR images were transferred through FTP using the ethernet network. 5.X and SPECT images were transferred using floppy diskets. Toprocess transferred images, an freely distributed software for Macintosh namely NIH Image, with its macrolanguage, was used to import images and translate header information. To identify necessary information, aseparate window named "Info-txt", was made for each image series. MacLC, Centris650, and PowerMac 6100/CD,7100/CD, 8100/CD models with 256 color and RAM over 8 Mbyte were used. RESULTS: Different versions of MR images and SPECT images were displayed simultaneously and a separate window named "Info-txt" was used to show all necessary information(name of the patient, unit number, date, TR, TE, FOV etc.). Additional information(diagnosis,pathologic report etc.) was stored in another text box in "Info-txt". The size of the file for each image planewas about 149 Kbytes and the images were stored in a step-like file folders. CONCLUSION: 4.X and 5.X GE Signa 1.5T images were successfully processed with Macintosh computer and NIH Image. This result may be applied to manyfields and there is hope of a broader area of application with the linkage of NIH Image and a database program.

MRI Findings of Peripheral Schwannoma: Pathologic Correlation

PURPOSE: To characterize the MRI appearance of the peripherally located schwannoma as compared with pathologic findings. MATERIALS AND METHODS: 11 cases of 13 lesions of the schwannoma confirmed by pathology were analyzed, retrospectively. T11 T2 and Gadolinium-enhanced T1 weighted sagittal and axial images were obtained. The signal intensity, contour of lesion, and relationship with surrounding tissue were analyzed. All cases were correlated with MRI and pathologic findings. RESULTS: In 9 out of the 11 cases, schwannoma was connected to the main nerve trunk. Among them, tumors were located centrally in 6 cases and eccentrically in 3 cases. MR findings of schwannoma were iso signal intensity on T1WI(8 cases) with muscle intensity, high signal intensity on T2WI(all cases), strong heterogenous enhancement in all cases. 8 cases showing heterogenous appearance on T2WI, showed mixture of Antoni-A and B area and multifocal hemorrhage. Central low and peripheral high signal intensity on T2Wl(Target sign) was mainly high cellular component in the central portion and diffuse myxoid degeneration at the periphery, pathologically. Reversed target appea.rance(central high, peripheral low on T2WI) revealed central cystic degeneration with low cellular component and hemorrhage in the central portion, and high cellular component at the periphery. Linear band-like low signal intensity on T2WI, suggesting capsule of the schwannoma, was not the true capsule proven by pathology. Thin true capsule was not visualized on T2WI. CONCLUSION: MR appearance of schwannoma was non-specific. The signal intensity on T2 weighted MR imaging was determined by the presence of multifocal hemorrhage, focal cystic and myxoid degeneration, admixture of Antoni-A and B area.

MRI Findings of Peripheral Schwannoma: Pathologic Correlation

PURPOSE: To characterize the MRI appearance of the peripherally located schwannoma as compared with pathologic findings. MATERIALS AND METHODS: 11 cases of 13 lesions of the schwannoma confirmed by pathology were analyzed, retrospectively. T11 T2 and Gadolinium-enhanced T1 weighted sagittal and axial images were obtained. The signal intensity, contour of lesion, and relationship with surrounding tissue were analyzed. All cases were correlated with MRI and pathologic findings. RESULTS: In 9 out of the 11 cases, schwannoma was connected to the main nerve trunk. Among them, tumors were located centrally in 6 cases and eccentrically in 3 cases. MR findings of schwannoma were iso signal intensity on T1WI(8 cases) with muscle intensity, high signal intensity on T2WI(all cases), strong heterogenous enhancement in all cases. 8 cases showing heterogenous appearance on T2WI, showed mixture of Antoni-A and B area and multifocal hemorrhage. Central low and peripheral high signal intensity on T2Wl(Target sign) was mainly high cellular component in the central portion and diffuse myxoid degeneration at the periphery, pathologically. Reversed target appea.rance(central high, peripheral low on T2WI) revealed central cystic degeneration with low cellular component and hemorrhage in the central portion, and high cellular component at the periphery. Linear band-like low signal intensity on T2WI, suggesting capsule of the schwannoma, was not the true capsule proven by pathology. Thin true capsule was not visualized on T2WI. CONCLUSION: MR appearance of schwannoma was non-specific. The signal intensity on T2 weighted MR imaging was determined by the presence of multifocal hemorrhage, focal cystic and myxoid degeneration, admixture of Antoni-A and B area.